As the use of radiated optical power of laser diodes has been increasing in recent years, the issue of eye safety has received an ever-increasing amount of attention. In the past, all laser applications were covered by the International Electrotechnical Commission (IEC) 60825 standard which is a laser safety standard (the disclosure of which is hereby incorporated by reference). Today, laser applications that deal with data transmission, projection devices and irradiation of objects, are covered by the IEC 60825 standard.
According to IEC 60825, for visual light (i.e. 400 nm≦λ<1050 nm), all pulses that reach a focal point within a period of time of 18 μs should be aggregated into a single pulse. This is due to the fact that during this period there is not enough time to allow the removal of heat accumulated at that focal point. However, for pulses that would arrive to that focal point after a period of 18 μs starting at their preceding pulse, heat transfer is a factor that may already be taken into consideration.
Typically (but not necessarily) three different lasers, each emitting at a different wavelength, are used to cover most of the color gamut of the human eye. These lasers are collimated and merged in order to produce a single beam with variable color, according to the specific combination of the three lasers intensities at that moment.
There is a need in the art to provide a method to enable increasing the intensity of a laser system while still being in conformity with the IEC Safety regulations, by taking advantage of the need to use several lasers in order to create the right color gamut.